1. Field of the Invention
The present invention relates to a semiconductor device having a bonding pad and a manufacturing method thereof, and more particularly, to a semiconductor device and a manufacturing method thereof, capable of preventing cracking from occurring in an inter-layer insulating film below a bonding pad and making finer an upper layer wiring formed in the same layer as the bonding pad.
2. Background Art
Semiconductor devices are provided with a bonding pad to exchange data with outside and apply a supply voltage or grounding voltage. When a semiconductor device is tested with a probe contacting this bonding pad or a wire is bonded to the bonding pad, there is a problem that an impact thereof causes a crack in an inter-layer insulating film below the bonding pad. Various semiconductor devices are proposed to solve this problem.
FIG. 22 is a cross-sectional view showing an example of a conventional semiconductor device. A plurality of metal plugs 35 are formed below a bonding pad 21. There is a metal layer 39 connected below the metal plugs 35, and metal layers 37 and 38 divided into a plurality of portions are formed below the metal layer 39. The plurality of metal plugs 35 can increase average Young's modulus of an inter-layer insulating film 17 below the bonding pad 21. Furthermore, the metal layers 37 to 39 display a buffering effect. This can improve resistance to impacts of probing and wire bonding (e.g., see Japanese Patent Laid-open No. 2005-243907, Japanese Patent Laid-open No. 2003-282627 and Japanese Patent Laid-open No. 2002-208610).
FIG. 23 is a cross-sectional view showing another example of the conventional semiconductor device. A bonding pad 21 has a first metal film 20 having high Young's modulus and a second metal film 24 having lower Young's modulus than the first metal film 20 formed on this first metal film 20. Forming the first metal film 20 having high Young's modulus over the entire surface of the area in which a pad opening 26 of a surface protection film 25 as the lower layer of the bonding pad 21 in this way can further improve resistance (e.g., see Japanese Patent Laid-open No. 2000-183104, Japanese Patent Laid-open No. 2003-324122 and Japanese Patent Laid-open No. 2005-223123).